1. Technical Field
This application generally relates to data storage, and more particularly to techniques used in connection with determining characteristics of protected data.
2. Description of Related Art
Computer systems may include different resources used by one or more host processors. Resources and host processors in a system may be interconnected by one or more communication connections. These resources may include, for example, data storage devices such as those included in the data storage systems, such as the data storage arrays manufactured by EMC Corporation. These data storage systems may be coupled to one or more host processors and provide storage services to each host processor. Multiple data storage systems from one or more different vendors may be connected and may provide common data storage for one or more host processors in a computer system.
A host processor may perform a variety of data processing tasks and operations using the data storage system. For example, a host processor may perform basic system I/O operations in connection with data requests, such as data read and write operations.
Host processor systems may store and retrieve data using a storage device containing a plurality of host interface units, disk drives, and disk interface units. Such storage devices are provided, for example, by EMC Corporation of Hopkinton, Mass. and disclosed in U.S. Pat. Nos. 5,206,939 to Yanai et al., 5,778,394 to Galtzur et al., U.S. Pat. No. 5,845,147 to Vishlitzky et al., and U.S. Pat. No. 5,857,208 to Ofek. The host systems access the storage device through a plurality of channels provided therewith. Host systems provide data and access control information through the channels to the storage device and storage device provides data to the host systems also through the channels. The host systems do not address the disk drives of the storage device directly, but rather, access what appears to the host systems as a plurality of logical disk units, logical devices, or logical volumes (LVs). The logical disk units may or may not correspond to the actual disk drives. Allowing multiple host systems to access the single storage device unit allows the host systems to share data stored therein.
Different techniques may be used in connection with providing data protection. Data protection may be provided by a data protection process that makes a copy of an original set of data. The copy of data may be used upon the occurrence of an event causing data failure such as may occur, for example, when the original copy of data is destroyed, corrupted, or otherwise unavailable. Different strategies may be used to provide data protection for different types of failures that can occur. A data protection policy (DPP) may be designed to meet data protection criteria or objectives determined in a variety of different ways. Such criteria may be specified in a service level agreement (SLA), by management or administrators, and the like. Once designed, the DPP may then be implemented. In connection with determining an implemented DPP, and more generally for other applications and uses of the protected data, it may be desirable to determine characteristics about the protected data using automated techniques.